Xoscillo source code?

[gustav...@hotmail.it]

Hi!

I'm looking for the Xoscillo's source code, but I can't find it on
this site.
I'm working to improve the arduino oscilloscope using an external adc,
and it would be easier to do having the source of the computer
program :)

Can you tell me where to download it?

Thank you in advance
Gustav.

[gustav...@hotmail.it]

Sorry guys, I found the code :)

[Raul Aguaviva]

Hey Gustav,

Probably for you the most interesting part would be the arduino's firmware, replacing the arduinos ADC acquisition with your own code should do it.

Please let me know if you have any questions!

Raul

[gustav...@hotmail.it]

Hi!
I needed the source code, because I use linux as primary OS. so I
compiled sources under linux and it works fine :)

I see that the arduino's firmware was written for arduino 2009, it
used an atmega 168, the last arduino uno has an atmega328P,which
should be better than the 168.
Does the 328 really work better? Can it give a better resolution?

Gustav

[Raul Aguaviva]

That's awesome, it sounds it wasn't too hard to get it working. 

As for the arduino code, yeah its for a 2009.. as for the 328p, I am not sure I should have to check the datasheet.. anyway the resoltion is good eought for my hobby projects...

BTW What are you using it for?

Raul

[gustav...@hotmail.it]

It's enough for my projects too :) I'll use it mostly for measure the
quality of some headphone amp.

It's kinda simple, I put a square wave in input, and with arduino i
see how much distorted is the output wave :)

But the point is another, I want to make something that can register
the negative wave too, because now I can't see if the amp has a Zero-
crossing distortion problem!

Merry Christmas :)
Gustav

[Raul Aguaviva]

Hey Gustav,

For audio amps I'd use a sine wave, a square wave has too many high freq harmonics that the headphone amp will have troubles amplifying. But given the low res of the arduino you'd probably wont see that :-) I guess you are usign an LM 328, right?

To get the negative side of the wave you'd need to use a couple of resistors to create a voltage divider and use that to offset the output of the amplifier

Merry Christmas to you too

Raul

[gustav...@hotmail.it]

Yeah it's right :D a square wave has too many high frequency, that's
why I wanna use it, I want to see how much Hi-Fi is the amp :)
A sine wave is too simple to amplify ;)

I don't understand the other part of the answer :) I can read only
positive tension with arduino can't I?
How a voltage divider could help me?

Thank you very much :)
Gustav

[gustav...@hotmail.it]

Ok, now I know how to use a voltage divider:

arduino pin
|
10K | 10k
---[5V]----^v^v----|----^v^v----[ -5V]

is it correct?

but...do I need 2 pins in order to read both positive and negative
voltage don't I?
Or there is a way that requires a single pin?

Thank you in advance :)
Gustav


On 26 Dic, 19:04, "gustav_yg...@hotmail.it" <gustav_yg...@hotmail.it>
wrote:

[Raul Aguaviva]

The voltage divider should go from 0V to 5V, that way it adds 2.5 volts to the output of your amp. You can assume ten that the top of the graph is 2.5 and the bottom -2.5.

Does it make sense?

Raul

[gustav...@hotmail.it]

Totally! thank you :)

but maybe i found another way :)
An opamp (powered with 3.3V) as voltage follower should be ok, in case
of voltage higher than 2Volt, i'll put an adjustable voltage divider
made by a potentiometer and a fixed resistance :)

On 30 Dic, 12:45, Raul Aguaviva <aguav...@gmail.com> wrote:
> The voltage divider should go from 0V to 5V, that way it adds 2.5 volts to
> the output of your amp. You can assume ten that the top of the graph is 2.5
> and the bottom -2.5.
>
> Does it make sense?
> Raul
>

> On Fri, Dec 30, 2011 at 11:50 AM, gustav_yg...@hotmail.it <

[Brett Cooper]

Would like to see how you wire that up. sounds like a very good solution to working with higher Volts than the Arduino can manage.

[gustav...@hotmail.it]

Here you are!

but instead of 500k resistance you have to use a linear potentiometer,
it's just a row schem, but it should work :)
Vcc is 3.3V

If you use a digital pot (managed by arduino) you can also know the
division factor and use it for set the right peak value in the
graph :)

I.E. (like in the picture) you know that the pot value is 500K, 500/10
= 50, you are measuring a peak of 2.6 V and the lowest value is 0.6V,
it's a +-1 sine wave, multiply +1 [and -1] * 50 and you get the real
voltage peaks :)

hope useful :)
Gustav

[gustav...@hotmail.it]

Google won't let me post the image... there's an E-mail for you :)

[hellonearthis]

Thanks. I have added the picture to a google doc in the hope others
will find this useful too.
https://docs.google.com/document/d/1Rem_ar0Dn3ZjyYQtMuYihPEc3fIvRHNi0isyBeww05o/edit

On Dec 31, 2:02 pm, "gustav_yg...@hotmail.it"

[gustav...@hotmail.it]

Great :)

I'm still working on it, i'll let you know if there's something wrong!

On 31 Dic, 03:03, hellonearthis <hellonearthis...@gmail.com> wrote:
> Thanks.  I have added the picture to a google doc in the hope others

> will find this useful too.https://docs.google.com/document/d/1Rem_ar0Dn3ZjyYQtMuYihPEc3fIvRHNi0...

[to...@hotmail.it]

Hi guys!
I'm gustav, I changed account, I'm posting for follow the group, sorry
for the spam :)

On 31 Dic, 10:52, "gustav_yg...@hotmail.it" <gustav_yg...@hotmail.it>
wrote:

[Raul Aguaviva]

Hi, I would put the voltage divider behind the cap, so you amp gets DC isolated from your probe

[to...@hotmail.it]

mmm....If I put the voltage divider after the cap, do I need a cap
that can support an high voltage, don't I?

[Raul Aguaviva]

It depends of the voltage swing of your amp... I doubt it will be more than 24 volts so any cap will do

[to...@hotmail.it]

Ok :)
Now I'm looking for a way to increase the sample rate, I heard that
the limit of 7Khz is due to the Serial function, but I also heard of a
library that could increase the baud rate of the serial
communication :)

[Raul Aguaviva]

You can get up to 1Mbit per sec, there is code for that checked in the tree

http://code.google.com/p/xoscillo/source/browse/firmware/ArduinoOscillo/HardwareSerial.cpp

Its not being used since it involved modifying some files in the arduino code code, and I thought that probably that would put off some people.

I hope this helps

Raul

[to...@hotmail.it]

Thank you very much man!!
I'll work on this things in a month, now I gotta study for the
University exams :)

On 2 Gen, 21:34, Raul Aguaviva <aguav...@gmail.com> wrote:
> You can get up to 1Mbit per sec, there is code for that checked in the tree
>

> http://code.google.com/p/xoscillo/source/browse/firmware/ArduinoOscil...

[蘇恆誠]

It's a good project.Where can  I get the C# source code.THKs 

gustav...@hotmail.it於 2011年12月12日星期一UTC+8下午8時43分04秒寫道：

[Raul Aguaviva]

OK, I'll assume that you have already used Google and that you have
already found the source code :)

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